Significance of serum NLRP3 as a potential predictor of 5-year death in hemodialysis patients: A prospective observational cohort study

Nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) is involved in inflammatory response. This study was done to explore the role of serum NLRP3 as a predictive biomarker of death after hemodialysis. In this prospective observational study of 331 patients undergoing maintenance hemodialysis, serum NLRP3 levels were measured. Univariate analysis and multivariate analysis were sequentially performed to determine predictors of 5-year death after hemodialysis. Age, major adverse cardiac and cerebral events (MACCE), and serum NLRP3 levels independently predicted 5-year mortality and overall survival (all P < .05). No interactions were found between serum NLRP3 levels and other variables, such as age, gender, hypertension, diabetes mellitus, primary renal diseases, and MACCE (all P interaction > .05). Serum NLRP3 levels were linearly correlated with risk of death and overall survival under restricted cubic spline (both P > .05) and substantially discriminated patients at risk of death under receiver operating characteristic curve (P < .001). Two models, in which age, MACCE, and serum NLRP3 were combined, were built to predict 5-year mortality and overall survival. The mortality prediction model had significantly higher predictive ability than age, AMCCE, and serum NLRP3 alone under receiver operating characteristic curve (all P < .05). The models, which were graphically represented by nomograms, performed well under calibration curve and decision curve. Serum NLRP3 levels are independently related to 5-year mortality and overall survival of patients after hemodialysis, suggesting that serum NLRP3 may be a potential prognostic biomarker of hemodialysis patients.


Introduction
Chronic kidney disease (CKD) is a major public health challenge worldwide. [1]CKD easily progresses into end-stage renal disease (ESRD), which refers to the inability of the kidneys to maintain fluid, electrolyte, and waste balance in the body. [2]ESRD greatly contributes to death of CKD patients. [3,4]Hemodialysis is widely recognized as an effective and frequently employed renal replacement therapy for ESRD patients. [5]9][10][11] Therefore, prognosis prediction is a very important step in clinical work of ESRD.14] The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is a critical component of the innate immune system and participates in inflammatory injury by mediating caspase-1 activation and regulating the release of pro-inflammatory cytokines interleukin-1β and interleukin-18. [15,16][19] Alternatively, activation of NLRP3 The authors have no funding and conflicts of interest to disclose.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
The ethical guidelines of the Declaration of Helsinki and its later amends were strictly obeyed during the study.The  inflammasome dramatically aggravated renal injury. [20]Also, NLRP3 inflammasome was activated in ESRD. [21]Therefore, serum NLRP3 may be a prognostic biomarker of ESRD patients undergoing hemodialysis.Here, serum NLRP3 levels were quantified at first-time hemodialysis of ESRD patients to further investigate its predictive significance for 5-year death after hemodialysis.

Study design, subject selection, and ethical consent
In this prospective observational study, maintenance hemodialysis patients were consecutively enrolled between January 2014 and June 2017 at the Quzhou Affiliated Hospital of Wenzhou Medical University.The exclusion criteria were as follows: dialysis duration <3 months; irregular dialysis; and presence of other specific conditions or diseases, for example, malignancies, infection within recent a month, and severe cardio-cerebral diseases.The ethical guidelines of the Declaration of Helsinki and its later amendments were strictly obeyed during the study.The study protocol was endorsed by the Institutional Review Committee at the Quzhou Affiliated Hospital of Wenzhou Medical University (approval number: LW2014-012).Participants volunteered to participate in the current study, and the legal representatives of patients in advance signed informed consent.

Data collections
Some baseline data were recorded, including age, gender, hypertension, and diabetes mellitus.During treatments, major adverse cardiac and cerebral events (MACCE) were identified.MACCE encompassed acute coronary syndrome, heart failure, cardiac death, and stroke. [22,23]In addition, urea reduction rate, post-dialysis weight, Kt/V, normalized protein catabolic rate, and residual creatinine clearance were calculated and then registered.Primary renal diseases were divided into chronic glomerulonephritis and other types.The patients were followed up until death or the completion of 5 years after first hemodialysis.The outcome parameter was death within 5 years.

immune analysis
Blood of patients was drawn via the median cubital vein.Some conventional laboratory data, including blood levels of intact parathyroid hormone, creatinine, albumin, hemoglobin, alkaline phosphatase, C-reactive protein, cholesterol, triglyceride, calcium and phosphate, hematocrit, and blood white blood cell counts were measured using the routine test methods.For measurement of serum NLRP3 levels, blood samples were put in 5 mL gel-containing biochemistry tubes (Hebei Free Trade Zone Shenghong Medical Equipment Co., Ltd., China), and after centrifugation, an aliquot of serum sample was extracted and afterward preserved in Eppendorf tubes (Eppendorf Tubes® BioBased, China) at a −80°C freezer for further immune analysis.Serum NLRP3 levels were quantified in batches.Blood samples, which were thawed every 3 months, were used for measuring serum NLRP3 levels.The sandwich enzyme-linked immunosorbent assay kit was purchased from Shanghai Zhenke Biotech Co., Ltd.(Shanghai, China).Detection range of the reagent kit was from 0.1 to 10 ng/mL.Its intra-assay coefficient of variation was <15%, with inter-assay coefficient of variation of <15%.A sandwich enzyme-linked immunosorbent assay reader was used to assess 450 nm optical density (Infinite M200 pro; Tecan®, Salzburg, Austria).Using blind method, all quantifications were in duplicate and completed by the same experienced technician.Double measurements were averaged for statistical analysis.Flowing diagram for selecting appropriate patients with hemodialysis.A cohort of 413 patients underwent an initial assessment in accordance with the enrollment criteria, and 331 patients were finally selected as eligible subjects for further clinical study after 82 patients were removed from this study.Among them, 302 patients were followed up until death or the completion of 5 yr.

Statistical analysis
The MedCalc statistical software version 17.4 (MedCalc Software, Mariakerke, Belgium), SPSS statistical package version 20.0 (SPSS Inc., Chicago, IL), and R software version 4.3.0(https:// www.r-project.org)were used for statistical analysis.All graphs were plotted using the GraphPad Prism statistical software version 8 (GraphPad Software, San Diego, CA).Data were presented as counts (percentages) if they were categorical variables, means (standard deviations) if they were normally distributed continuous variables, and medians (interquartile ranges) if they were non-normally distributed continuous variables.Statistical methods for comparing data between 2 groups included the Pearson Chisquare test, independent t test, and Mann-Whitney U test.Under the restricted cubic spline, linear correlations of serum NLRP3 levels with risks of 5-year death and overall survival were reported.The binary logistic regression model, in which 5-year mortality was selected as the dependent variable, was built to discern the factors, which independently influenced 5-year mortality of hemodialysis patients.Associations were presented as odds ratios with the corresponding 95% confidence intervals (95% CIs).Discriminatory ability was assessed under receiver operating characteristic (ROC) curve.The results were reported as area under ROC curve (AUC) and Z test was done for comparisons of AUCs.The prediction model, in which the independent factors of 5-year mortality were incorporated, was described using the nomogram.The prediction efficiency of the model was assessed using the ROC curve, its prediction fit was determined using the Hosmer-Lemeshow goodness of fit statistics and calibration curve analysis, and its clinical effectiveness was investigated using the decision curve analysis.Survival curves were generated according to the Kaplan-Meier method.The log-rank test was performed to complete the comparison of 5-year overall survival between 4 subgroups, which was formed according to median and lower-upper quartile values of serum NLRP3 levels.The multivariate Cox proportional hazard model, in which 5-year overall survival time was regarded as the dependent variable, was established to ascertain independent predictive parameters.The Cox regression coefficients were used to generate a nomogram.The calibration curve for the 5-year survival probability was used to evaluate the relationship between the nomogram prediction and actual observation.The decision curve was used to evaluate the clinical utility.Using subgroup analysis, interactions with age, gender, hypertension, diabetes mellitus, primary renal diseases, and MACCE were investigated.Using the MedCalc statistical software version 17.4 (MedCalc Software), the sample size was sufficient for clinical analysis.The 2-sided P values < .05were deemed as statistically significant differences.

Participant characteristics
During the study period, an aggregate of 413 patients with hemodialysis were initially recruited, afterward, 82 patients were excluded because of reasons outlined in Figure 1, and finally, 331 patients were analyzed.Among them, 302 patients were followed up until death or the completion of 5 years.In Table 1, there were non-statistically significant differences in terms of demographic, clinical, and biochemical data between those 302 and 331 patients (all P > .05).

Serum NLRP3 levels and 5-year mortality of patients with hemodialysis
Altogether, a 5-year follow-up was completed in 302 patients.Among them, 107 patients (35.4%) died and 195 patients *A total of 331 hemodialysis patients were eligible for final analysis (the first group) and 302 patients were followed up until death or the completion of 5 years after hemodialysis (the second group).
(64.6%) survived.In Table 2, non-survivors were significantly older than survivors (P < .001),serum NLRP3 levels, serum C-reactive protein levels and blood white blood cell counts were substantially higher in the dead than in the alive (all P < .05),and the deceased exhibited markedly higher percentages of MACCE, hypertension, and diabetes than other remainders (all P < .05).The above-mentioned 7 significant variables were all forced into the binary logistic regression model and thereafter it was revealed that age, serum NLRP3 levels, and MACCE emerged as the 3 independent predictors of death in hemodialysis patients (all P < .05;Table 3).In Figure 2, serum NLRP3 levels were linearly related to the risk of death in hemodialysis patients under restricted cubic spline (P = .100).Serum NLRP3 levels significantly discriminated the risk of death in hemodialysis patients (AUC, 0.765; 95% CI, 0.713-0.811).Using the Youden method, serum NLRP3 levels more than 2.14 ng/mL predicted 5-year death with the maximum Youden index of 0.427 (Fig. 3).Interestingly, in contrast to age (AUC, 0.631; 95% CI, 0.574-0.686)and MACCE (AUC, 0.691; 95% CI, 0.636-0.743),serum NLRP3 levels had a substantially higher predictive value (P = .0016and .0346,respectively).Subgroup analysis showed that no substantial interactions occurred between serum NLRP3 levels and other variables, such as age, gender, hypertension, diabetes mellitus, primary renal diseases, and MACCE (all P > .05;Fig. 4).In addition, the combined model was composed of serum NLRP3 level, age, and MACCE.Next, the combined model was visually reflected by a nomogram, which was constructed to assess the risk of death in hemodialysis patients (Fig. 5).The prediction model had comparative stability using calibration curve analysis (Fig. 6).Furthermore, the prediction model was clinically effective using decision curve analysis (Fig. 7) and had a significant discriminative effect on the risk of death in hemodialysis patients (AUC, 0.804; 95% CI, 0.755-0.847;Fig. 8).Moreover, the combined model had dramatically higher AUC than each one of the preceding 3 factors (all P < .05;Fig. 8).

Serum NLRP3 levels and 5-year overall survival of hemodialysis patients
Mean 5-year overall survival time was 53.0 months (95%       in serum NLRP3 levels (P < .001;Fig. 9).In Figure 10, serum NLRP3 levels were linearly correlated with overall survival risk under restricted cubic spline (P = .098).Table 4 shows that age, diabetes mellitus, hypertension, MACCE, serum NLRP3 levels, serum C-reactive protein levels, and blood white blood cell counts were significantly associated with 5-year overall survival of hemodialysis patients (all P < .05).The above-mentioned 7 significant variables were all forced into the multivariate Cox regression model and afterward it was found that serum NLRP3 levels, age and MACCE retained as the 3 independent predictors of 5-year overall survival in hemodialysis patients (all P < .05;Table 5).Also, there were no marked interactions between serum NLRP3 levels and age, gender, hypertension, diabetes mellitus, primary renal diseases, and MACCE (all P > .05;Fig. 11).The nomogram was constructed to predict the probability of 5-year overall survival of hemodialysis patients (Fig. 12).The calibration curve showed good agreement between predicted and observed outcomes for 5-year overall survival prediction model (Fig. 13).Decision curve analysis confirmed the clinical effectiveness of the prediction model (Fig. 14).

Discussion
To the best of our knowledge, it is unclear whether serum NLRP3 levels may be correlated with 5-year mortality in incident hemodialysis patients.In this study, we found that serum NLRP3 levels were significantly increased with decreasing 5-year overall survival time and were substantially higher in the deceased than in the alive within 5 years after hemodialysis; serum NLRP3 levels were independently associated with 5-year mortality and overall survival of patients with hemodialysis; 2 models containing serum NLRP3 levels, age, and MACCE performed well in prediction of death and overall survival at 5 years after hemodialysis in such patients.Overall, the preceding data are strongly supportive of the presumption that serum NLRP3 may be of clinical significance as a potential prognostic biomarker in hemodialysis patients.Among patients undergoing hemodialysis, MACCE is easily encountered, which is associated with significantly heightened risk of death. [24,25]28][29] In this cohort, 5-year MACCE incidence was approximately 50%, indicating that its incidence may be significantly elevated with increasing follow-up time.MACCE has been demonstrated to be an independent risk factor of death in hemodialysis. [30]onsistently, MACCE was independently associated with 5-year mortality in our study.Taken together, MACCE may be a common complication of patients under hemodialysis, which should be paid intensive attention and treated during hemodialysis.
ESRD is very frequently complicated with other tissue injuries. [31]Hemodialysis patients mainly die of multiple organ dysfunction or failure, which is related to systemic injures. [32]athophysiological mechanisms underlying systemic injures in ESRD involve inflammation, oxidative stress, cellular apoptosis, etc. [33] Thus, a circulating biomarker, which is able to reflect status of systemic injuries, may be a potential predictor of death among hemodialysis patients.
[38][39][40][41] Diabetic and hypertensive nephropathies are the 2 main causes of ESRD.In a study of diabetic nephropathy, which contained in vitro and in vivo data, NLRP3 inflammasome was found to be activated. [42]NLRP3 inflammasome activity may be involve in the blood pressure fluctuation and kidney injury. [43]Overall, NLRP3 may be a potential systemic inflammatory biomarker, which could reflect not only renal injury, but also systemic injury.
In this study, a total of 331 finally recruited patients were included in compliance with inclusion and exclusion requirements.To investigate the association between serum NLRP3 levels and 5-year overall survival of hemodialysis patients, patients were divided into 4 subgroups based on the tertiles of serum NLRP3 levels.Clearly, the 5-year overall survival rates were significantly declined with increasing serum NLRP3 levels from Q1 to Q4 among patients.Moreover, using multivariate analysis, serum NLRP3 levels were independently associated with 5-year overall survival of patients undergoing hemodialysis.In addition, a total of 302 were followed up until death or the completion of 5 years, and subsequently were divided into 2 subgroups, namely, the deceased and the alive groups.As opposed to all patients, this group of patients had non-statistically significant differences in terms of demographic, clinical, and biochemical data, indicating this group of patients could represent the whole group of patients.Consistently, serum NLRP3 levels were independently associated with 5-year death after hemodialysis.The above data were strongly supportive of the assumption that higher serum NLRP3 levels may be linked to higher risk of 5-year mortality in hemodialysis patients.Thus, serum NLRP3 may be a potential biomarker of long-term death among hemodialysis patients.
In present study, serum NLRP3 levels were linearly correlated with death of hemodialysis patients.Besides serum NLRP3, the other 2 independent factors of 5-year death were age and MACCE, which have been confirmed to be commonest predictors of death among hemodialysis patients.In current study, serum NLRP3, age, and MACCE had AUCs at 0.765, 0.631, and 0.691, respectively.Among them, serum NLRP3 displayed significantly highest death prediction ability in terms of AUC.Moreover, serum NLRP3, age, and MACCE were merged in a prediction model, which was revealed to take possession of significantly highest AUC, as compared to other 3 predictors alone.The model was visually described using a nomogram.Using calibration curve analysis and decision curve analysis, the model was comparatively stable and clinically valuable for predicting 5-year death of hemodialysis patients.This indicates that the combined model can be used as a good predictor of mortality risk in hemodialysis patients.
There are several strengths and weaknesses in the current study.The strengths are that to the best of our knowledge, serum NLRP3 levels were determined in hemodialysis patients for the first time, and subsequently it was found that serum NLRP3 may be a useful prognostic biomarker of hemodialysis patients with ESRD; in order to offer more evidence to support the conclusion, both 5-year mortality and overall survival were applied to reflect prognosis of hemodialysis patients, and associations of serum NLRP3 levels with them were verified using univariate analysis followed by multivariate analysis.The weaknesses are that the present study was based on Chinese patients.Further validation with diverse populations and races is essential; the present study is a single-center study and therefore the reproducibility of the current findings should be further validated in a larger cohort study or a multicenter study.

Conclusions
Serum NLRP3 levels of hemodialysis patients are independently associated with 5-year mortality and overall survival.Under ROC curve, serum NLRP3 levels show higher death prediction ability, as compared to other 2 independent predictors, that is, age and MACCE.Meanwhile, the combined model, which is composed of serum NLRP3 levels, age, and MACCE, significantly improves their discriminatory efficiency for the risk of death in hemodialysis patients.Moreover, such a model is of stability and has comparatively high clinical value.Thus, serum NLRP3 may be used as a good predictor of 5-year mortality of patients undergoing hemodialysis.www.md-journal.comFigure 11.Subgroup analysis assessing interaction between serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels and other variables for predicting 5-yr overall survival of hemodialysis patients.Serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels had no substantial interaction with age, gender, hypertension, diabetes mellitus, primary renal diseases, and major adverse cardiac and cerebral events (all P > .05).95% CI = 95% confidence interval, HR = hazard ratio, MACCE = major adverse cardiac and cerebral events.

Figure 1 .
Figure1.Flowing diagram for selecting appropriate patients with hemodialysis.A cohort of 413 patients underwent an initial assessment in accordance with the enrollment criteria, and 331 patients were finally selected as eligible subjects for further clinical study after 82 patients were removed from this study.Among them, 302 patients were followed up until death or the completion of 5 yr.

Figure 2 .
Figure 2. Restricted cubic spline showing the linear relationship between serum nucleotide-binding oligomerization domain-like receptor family pyrin domaincontaining 3 levels and the risk of 5-yr death after hemodialysis.Serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels were linearly related to the risk of 5-yr death in hemodialysis patients (P > .05).95% CI = 95% confidence interval, NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3, OR = odds ratio.

Figure 3 .
Figure 3. Receiver operating characteristic curve of serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels for predicting 5-yr mortality of hemodialysis patients.Using the Youden method, serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels >2.14 ng/mL distinguished the risk of death in hemodialysis patients with medium-high specificity and sensitivity.

Figure 4 .
Figure 4. Subgroup analysis discerning interaction between serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels and other variables for predicting 5-yr mortality of hemodialysis patients.No significant interactions were found between serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels and age, gender, hypertension, diabetes mellitus, primary renal diseases, and major adverse cardiac and cerebral events (all P > .05).95% CI = 95% confidence interval, MACCE = major adverse cardiac and cerebral events, OR = odds ratio.

Figure 5 .
Figure 5. Nomogram describing the prediction model of the risk of 5-yr death in hemodialysis patients.A nomogram was constructed to visually display the prediction model of 5-yr mortality of patients with hemodialysis, in which serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age, and major adverse cardiac and cerebral events were integrated.MACCE = major adverse cardiac and cerebral events, NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3.

Figure 6 .
Figure 6.Calibration curve showing stability of the predictive model of 5-yr mortality of patients with hemodialysis.The prediction model remained stable for the prediction of 5-yr mortality after hemodialysis the calibration curve.

Figure 7 .
Figure 7. Decision curve exhibiting the clinical benefit of the prediction model of 5-yr mortality of patients with hemodialysis.The prediction model, which contained serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age and major adverse cardiac and cerebral events, was clinically beneficial in predicting the risk of 5-yr death in hemodialysis patients.MACCE = major adverse cardiac and cerebral events, NLRP3 = nucleotidebinding oligomerization domain-like receptor family pyrin domain-containing 3.

Figure 8 .
Figure 8. Receiver operating characteristic curve with respect to discriminatory ability of the prediction model for the risk of death in hemodialysis patients.The prediction model, which contained serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age, and major adverse cardiac and cerebral events, had a significantly higher predictive ability for the risk of death in hemodialysis patients, in contrast to each one of the preceding 3 factors (all P < .05).95% CI = 95% confidence interval, AUC = area under curve, MACCE = major adverse cardiac and cerebral events, NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3. *P < .05;**P < .01.

Figure 9 .
Figure 9. Survival curve showing 5-yr overall survival after hemodialysis across serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels.Patients were divided into 4 groups according to percentiles 25th, 50th, and 75th of serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels: Q1, Q2, Q3, and Q4.Using the log-rank test, survival rates decreased significantly with an increase in serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels (P < .001).

Figure 10 .
Figure 10.Restricted cubic spline ascertaining the linear relation of serum nucleotide-binding oligomerization domain-like receptor family pyrin domaincontaining 3 levels to the risk of 5-yr overall survival after hemodialysis.Serum nucleotide-binding oligomerization domain-like receptor family pyrin domaincontaining 3 levels were linearly correlated with the risk of 5-yr overall survival in hemodialysis patients (P > .05).95% CI = 95% confidence interval, HR = hazard ratio, NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3.

Figure 12 .
Figure 12.Nomogram describing the prediction model of the probability of 5-yr overall survival of hemodialysis patients.A nomogram, in which serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age, and major adverse cardiac and cerebral events were merged, was constructed to visually display the prediction model of 5-yr overall survival of patients with hemodialysis.Draw a line down to the morbidity axes to determine the possibility of 5-yr overall survival of hemodialysis patients.MACCE = major adverse cardiac and cerebral events, NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3.

Figure 13 .
Figure 13.Calibration curve exhibiting the stability of the prediction model of 5-yr overall survival of patients with hemodialysis.The prediction model, which contained serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age and major adverse cardiac and cerebral events, was stable in predicting 5-yr overall survival in hemodialysis patients.

Figure 14 .
Figure 14.Decision curve exhibiting the clinical benefit of the prediction model of 5-yr overall survival of patients after hemodialysis.The prediction model, which contained serum nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 levels, age and major adverse cardiac and cerebral events, was clinically beneficial in predicting 5-yr overall survival in hemodialysis patients.MACCE = major adverse cardiac and cerebral events, NLRP3 = nucleotidebinding oligomerization domain-like receptor family pyrin domain-containing 3.
study protocol was endorsed by the Institutional Review Committee at the Quzhou Affiliated Hospital of Wenzhou Medical University (opinion number: LW2014-012).Participants volunteered to participate in the current study, and the legal representatives of patients in advance signed informed consent.
a Department of Nephrology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People's Hospital, Quzhou, China, b Department of Nephrology, Quzhou KeCheng People's Hospital, Quzhou, China, c Traditional Chinese Medicine Department, Quzhou Hospital of Zhejiang Medical and Health Group, Quzhou, China.

Table 1
Basic data of the hemodialysis patients.
Data were shown as counts (percentages), means ± standard deviations or medians (upper-lower quartiles) where appropriate.Intergroup comparisons were done using the Chi-square test, Fisher exact test, Student t test, or Mann-Whitney test as appropriate.NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3.

Table 2
Differences of basic data between non-survivors and survivors among 302 hemodialysis patients.
Data were shown as counts (percentages), means ± standard deviations, or medians (upper-lower quartiles) where appropriate.Intergroup comparisons were done using the Chi-square test, Fisher exact test, Student t test, or Mann-Whitney test as appropriate.NLRP3 = nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3.

Table 3
Multivariate logistic regression analysis of death among 302 hemodialysis patients.